Hello im having some issue with coding union probability in R as i am quite new to the language

p(a) = 0.30
p(b)=0.45
p(c)= .40

I am trying to find the p(at least one of three items have been purchased) which is p(AuBuC)

ive tried using dbinom but have recently learned that it only works when all three have the some probability

union(A,B) doesn't seem to work either:

A=0.30
> B=0.45
> C=0.40
> union(A,B,C)

Error in union(A, B, C) : unused argument (C)

any ideas, tips or pointers?